Numerous biomedical applications require rapid and precise identification and quantitation of biomolecules present in relevant biological and environmental samples. The starting point in such experiments is an appropriate sample preparation procedure, which often determines if the experimental outcome is successful or not. For example, sample collection, pre-purification, and preparation procedures are crucial in molecular diagnostics such as genomic and proteomic analyses. These analyses usually depend on specific hybridization or affinity binding between DNA/RNA/protein targets (unknown) and probes (known). The specificity of hybridization or affinity binding can be negatively affected by the presence of abundant impurities. Furthermore, the concentration of target molecules may vary by many orders of magnitude and fall out of the dynamic range of the biosensors used to detect them.
Despite the importance of sample preparation methods, no universal or standard sample preparation protocols exist in the biomedical community. Variations in sample preparation may contribute to major discrepancies in the quantity and type of biomolecules identified by different laboratories, even though the same reagents and biosensors (or biochips) are employed. Therefore, better and more affordable sample preparation methods and tools are still in great demand.
There are a number of devices available for sorting or capturing biomolecules of interest using magnetic sorters. With these devices, a wall of the device contains a magnet, fluid is passed over the magnet in a planar configuration, and magnetic probes attached to a biomolecule of interest sticks to the magnet, allowing impurities to pass through. These devices have a number of shortcomings, including large size, low capture rates, low flow rates, and cumbersome methods of releasing captured biomolecules. Accordingly, there is a need in the art to develop a new magnetic device that is small in scale, enables three dimensional flow normal to the substrate, allows relatively higher flow rates and higher capture rates, and provides a relatively easy method of releasing captured biomolecules.